stack.hpp

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/* src/vm/jit/stack.hpp - stack analysis header

   Copyright (C) 1996-2014
   CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO

   This file is part of CACAO.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

*/


#ifndef STACK_HPP_
#define STACK_HPP_ 1

#include "config.h"                     // for ENABLE_VERIFIER
#include <stdint.h>
#include "vm/global.hpp"                // for Type

struct instruction;
struct jitdata;

/* stack element structure ****************************************************/

enum VariableFlag {
    SAVEDVAR    =   1,   // variable has to survive method invocations
    INMEMORY    =   2,   // variable stored in memory
    SAVREG      =   4,   // allocated to a saved register
    ARGREG      =   8,   // allocated to an arg register
    PASSTHROUGH =  32,   // stackslot was passed-through by an ICMD
    PREALLOC    =  64,   // preallocated var like for ARGVARS.
                         // Used with the new var system
    INOUT       = 128    // variable is an invar or/and an outvar
};

// check flags
static inline bool IS_SAVEDVAR(s4 flags) { return flags & SAVEDVAR; }
static inline bool IS_INMEMORY(s4 flags) { return flags & INMEMORY; }


enum VariableKind {
    UNDEFVAR = 0,   // stack slot will become temp during regalloc
    TEMPVAR  = 1,   // stack slot is temp register
    STACKVAR = 2,   // stack slot is numbered stack slot
    LOCALVAR = 3,   // stack slot is local variable
    ARGVAR   = 4    // stack slot is argument variable
};

/* variable kinds */
struct stackelement_t {
    stackelement_t *prev;       /* pointer to next element towards bottom     */
    instruction    *creator;    /* instruction that created this element      */
    Type            type;       /* slot type of stack element                 */
    int32_t         flags;      /* flags (SAVED, INMEMORY)                    */
    VariableKind    varkind;    /* kind of variable or register               */
    int32_t         varnum;     /* number of variable                         */
};


/* function prototypes ********************************************************/

bool stack_init(void);

bool stack_analyse(jitdata *jd);

void stack_javalocals_store(instruction *iptr, int32_t *javalocals);

#endif // STACK_HPP_


/*
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